An ink jet printer is as an example of a printing apparatus that ejects droplets of ink onto a recording medium such as a sheet of paper, for printing an image of the recording medium. The ink jet printer includes a head unit having at least one ink jet head provided with an ink cartridge that accommodates the ink. In operation of the head unit, the ink is supplied from the ink cartridge to each ink jet head having ejection nozzles, so that a printing operation is performed by ejection of the ink droplets from selected ejection nozzles.
High speed ink jet printers typically include a fixed print head unit, where only the substrate (e.g. paper) moves. However the product of such high speed, single pass ink jet printers results in various defects, such as streaks, bands, non-uniformities and white lines due to jet outs and deviated jets. Therefore, to produce high print quality either the printing speed is to be reduced or more ink is required to print. Nonetheless, some defects might persist despite such precautions being taken.
Accordingly, a mechanism to maximize print quality in high speed jet printers is desired.